Indicating and recording device for yarn diameters



J 1953 F. P- STROTHE R INDICATING AND RECORDING DEVICE FOR YARNDIAMETERS s Sheets-Shet 1 Filed May 14, 1947 v JNVENTORQ FRED STROTHER IATTORNE June 16, 1953 F. P. STROTHER 2,641,960

INDICATING AND RECORDING DEVICE FOR YARN DIAMETERS Filed May 14, 1947 sSheets-Sheet 2 INVENTOR.

FRED' P. STROTHER JTTORNEY Patented June 16, 1953 nmrso STATES, PATENTorrics INDICATING AND RECORDING DEVICE FOR YARN DIAMETERS 7 Fred P;Strother, Old Greenwich, Conn, assignor to Deering Milliken ResearchTrust, New York,

N. Y., a nonprofit trust of New .York

Application May 14, 1947, Serial No. 148,081

The present invention relates to measurement which the sliversandrovingspass in the process of yarn production. For example, uneven orworn rollers in the sliver lapping machine, or the sliver draftingorlong draft roving machines or in the yarn spinning machine itself, willcause periodic variations'in yarn diameter, as will irregularities inthe builder motion of the ring spinning machine. If there is faultyoperation of two or more of the machines, yarn diameter variations of acorrespondingnumber of periodicities will result. As a general rule,because of the series of drafting operations, the longer the periodicityof the diameter variations, the further back into the history of theprocessing of the yarn will be found the source of the trouble. When twoor moreperiodicities occur simultaneously, a corresponding number offaulty machine elements'may be expected. Thus, if yarn diametervariationscan be recorded and-alalyzed so as to determine the number ofdifierent periodicities of the deviations occurring in the yarn, thesource or sources of the deviations may be located and corrected beforethe yarn is Woven into fabric, thus aiiording a substantial saving inmaterial, time and labor.

An object of the invention is, therefore, to provide accurate means forcontinuously measuring and recording yarn diameter.

7 Another object of the invention is to provide means for obtaining arecord of yarn diameter which discloses periodic diameter variations.

A further object of the invention is to provide means for analyzing andrecording yarn diameter variations in accordance with their pcriodicity.Q

Other objects of the invention will become ap parent as the descriptionproceeds.

For an understanding of the invention refer ence may be had to theaccompanying drawings of which: s

V Fig. 1 is a diagram of a yarn diameter measuring and recording deviceembodying the invention;

Fig. 2 is a diagram similar to Fig. 1 but illusis ciaims. (01. 88-14)trating an alternative form of measuring circuit;

Fig. 3 is a diagram showing the type of records obtained with thedevice'of either Fig. 1 or Fig. 2; a Fig. 4: is a diagram of a yarndiameter measuring, analyzing and recording device embodying theinvention; and

Fig. 4a. is a diagrammatic View illustrating an alternative arrangementfor a part of the device of Fig. 4.

In Fig. 1, the yarnZ, the diameter of which is to bemeasured, is movedatv av constant speed in the direction of the arrow as by rollers 3. Theyarn 2 passes through a beam of light which issues from a source 4 andis directed by a lens and aperture system 6 toward a photocell- 8 po--,sitioned to respond thereto. A balancing photocell ii! is positioned torespond to the light from source s after passage through a slit or lightvalve 12. vIn the particular measuring circuit shown in Fig. 1, theanode of cell It and the cathode of cell 8 are connected together and toone end of a resistor M. The other end of resistor I4 is connected tothe negative terminal of a battery it and'to the positive terminal of abattery It; the positive terminal of battery 16 being connected 'to theanode of cell 8 and the negative terminal of battery L8 being connectedto the cathodeof cell' H3. Withthis arrangement, batteries 16 and It!being of equal voltage, no. current will flow through resistor 14 whenthe currents through the cells 8 and II) are equal. By any suitableadjustment, as of the light valve vl2, these currents may be madeequalfor any desired diameter of yarn 2. Departure of the yarn diameterfrom the desired value causes current to flow through resistor M, thedirection of the current depending upon increase or decrease of yarndiameter and the magnitude of the current depending upon the magnitudeof the yarn diameter variation. The potential difi'erence acrossresistor M resulting from unbalance of the photocell currents due toyarn diameter variations is amplified and used to controlrecordingdevices. In the particular circuit of Fig. 1, amplification of thepotential difference across resistor 14 is effected by tubes 20 and 22,which maybe GAGE tubes. As shown, these tubes havetheir control gridsconnected across resistor I4, their plates connected through aresistance 24,-

3 difference appears across resistor 24 when cur rent flows throughresistor l4 due to change in the yarn diameter from the predeterminedvalue. This amplified potential difference across resistor 24 is appliedto the input terminals of a power amplifier shown within the: dashedenclosure 28 as a cathode follower. The double triode. 29 of the poweramplifier, which may be a 6AS'7G, has its control grids connected toopposite ends of resistor 24, its cathodes connected by a centergrounded resistor 34, and its plates connected to the power supply,indicated by B+. A winding 30, of a motor 32 is connected acrossresistor 34. Thus, motor 32 is energized only when the yarn diameterdeparts from the desired value, energization being in one direction whenthe yarn diameter increases, and in the other direction when the yarndiameter decreases. Motor 32, which may be, and preferably is, a. penmotor, thus responds up to the limit of its sensitivity to each changein yarn diameter and hence a complete record of yarn diameter variationsmay be made upon a chart moved beneath the motor pen in timed relationwith the feeding of a length of yarn past the photocell 8.

In Fig. 3, a graph, typical of the record obtainable by the motor 32, isindicated at A. The graph A is a record of all diameter variationsofsufficient magnitude and duration to energlze the motor 32. With theabove described measuring and amplifying circuits, the apparatus may bemade suificiently sensitive to measure diameter variations of as littleas one ten thousandth of an inch. The minimum duration of the diametervariations sufiicient for accurate response of the motor depend, ofcourse, upon the rate at which the yarn is fed through the meter. With afeed of yarn of ten feet per second, the motor can be sensitive enoughto portray diameter variations of one-half inch or more duration.

To record average diameter variations, a second motor 32a is provided,the winding 30a, of which is energized through a power amplifier 28aconnected to the output of amplifying tubes and 22, isolating resistors36 being inserted in the leads to the control grids. of the poweramplifier, and damping condensers 38 being connected across the windinga. With this arrangement, the motor 32a integrates the variations andyields a graph such as B on Fig. 3. Motors'32 and 320. are preferably,but not necessarily, arranged to trace their respective graphs on thesame chart.

In the particular measuring circuit disclosed in Fig. 1, variations inintensity of the light source at any moment will not unbalance thephotocell currents as they will be equally affected. However, if thelight intensity varies from time to time, the same magnitude of changein yarn diameter at different light intensities will show up in thegraphs A and B as deviations of different magnitudes from theirrespective base lines 40. In order to insure that deviations of thegraph A of equal magnitude correspond to equal diameter variations,irrespective of variations of light intensity, the cell l0, instead ofbeing connected as a balancing cell for the cell 8 could be connectedthrough an automatic volume control device to the amplifier circuit.Such an arrangement is illustrated in Fig. 2. Fig. 2 illustrates also analternating rather than direct current type of measuring circuit.

In Fig. 2, the filament of lamp 4 is connected in series with a battery40 across a suitable source of alternating current, indicated as thesecondary winding of a supply transformer 4|. Photocell 8 is connectedin series with a resistor Ma across the battery I611, and photocell I0is connected in series with a resistor 42 across the battery lBa. Thecontrol grid of an amplifier 43 is connected through a condenser 44 withthe low potential end of resistor [4a, and the suppresser grid ofamplifier 43 is connected to ground through a resistor 45. The potentialacross resistor 45 is controlled through an automatic volume controldevice, indicated diagrammatically at 46 from the circuit of cell [0.The output circuit of amplifier 43 is connected through a phase inverter41 to the inputs of cathode followers 28 and 28a for energization ofmotors 32 and 32a. With this arrangement, .motors 32 and 32a. areenergized continuously and an increase and decrease of yarn diameterfrom a predetermined value causes increase and decrease, respectively,in the motor current. The base lines 40 of Fig.

3 thus correspond, for the embodiment of Fig.

in the suppresser grid lead of amplifier 43, graphs tracedby the motors32 and 32a will be independent of light intensity variations.

The scale of the chart of Fig. 3, in the par ticular embodiment of theinvention illustrated,

is such that one horizontal division corresponds to two'feet of yarn andone vertical division corresponds to .001 inch. From graphs A and B, thepattern of diameter variations of the first fifteen horizontal divisionscan be recognized in the second fifteen horizontal divisions and henceperiodicities of diameter variations of not more than thirty feet areindicated in the particular sample of yarn tested. Periodicities ofsubstantially less than thirty feet are also indicated by the graphs andcould be specifically determined by careful analysis of curve A. Theclosely spaced deviations of graph A indicate short pe-. riod variationssuch as slubs, etc. From graph B it is apparent that the averagediameter variations of any length of the yarn do not exceed .0005 plusor minus.

In Fig. 4 a complete yarn diameter meter, analyzer and recorder isillustrated. In the particular embodiment of the invention illustratedin Fig. 4, the analyzer is equipped to detect and record elevendifferent periodicities as well as the presence of periodicities of overa given value. The measuring circuit is only diagrammatically indicatedin Fig. 4. It may beassumed to be that of either Fig. l or that of Fig.2. The output from amplifier 48 controls, through power amplifiers 28and 28a, the pen motors 32 and 32a, respectively. Amplifier 48 may beassumed to be the direct current amplifier comprising the tubes 20 and22 of Fig. 1 or the amplifier 43 and phase inverter 41 of Fig. 2. Inorder to analyze the graph produced by motor 32, the amplifier 48 isconnected to eleven similar analyzing circuits each arranged to selectand pass a different frequency component of the amplifier output andeach arranged to control the energization of a pen motor. To simplifythe description, specific frequencies corresponding to definiteperiodicities for a speed of yarn through the meter of ten feet persecond will be described. The analyzer circuit of pen motor 32b passescurrent of .25 cycle, corresponding to diameter deviations recurring atforty-foot intervals; the circuit for motor 320 passes a current of .5cycle;

that for motor 32d, 1' cycle; for motor 32e,.2' cycles; motor 321, 4cycles; motor 32y, 7.5 cycles; motor 32h, 15 cycles; motor 321, 30cycles; and for motors 329', 32k and 32m, 60, 120 and240 cycles,respectively. This gives an analyzing range of periodicities fromone-half inch to forty feet and has been found to be sufficient todetect practically every periodic diameter'variationnormally'encountered in yarn manufacture. In addition, there is providedone pen motor 3211 which indicates roughness of the yarn, its analyzingcircuit passing frequencies above 480 cycles. In Fig. 4, the analyzingcircuit for motor 32b, includes two series connected amplifiers 54b and56b bridged by feed back elements 58b and 601), respectively. Amplifiers54b and 5617' may each be a 6AG5, and elements 581) and 6017 areparallel T networks having constants such that the maximum response ofamplifierfidb is to a frequency slightly less than .25 cycle, and themaximum response of amplifier 56b is to a frequency slightly higher than.25 cycle. The output from amplifiers 54b and 56b is amplified by anamplifier 62!), which may be a 68.17, after passage througha high bandpass filter 64b and is then delivered, through a low band pass filter66b, to the power'amplifier or cathode follower 281); the filters 64band 66b being constructed to have overlapping pass bands in .the regionof .25 cycle. Thus, if diameter deviations in the yarn 2 recur atintervals of 40 feet, the pen of motor 321) will'trace the curve 22 onthe moving chart 68.. The chart 68 is driven at constant speed by amotor H1, and the chart is provided with a graduated transverse scale l2so that the'magnitude of the diameter deviations may be read directlyfrom the scale. A grad uated longitudinal scale 14 may be provided, if

desired, for, readyinterpretation of the curves A and B traced by penmotors 32 and 32a. 7 A study of curve b indicates not only that diameterdeviations do recur at foot intervals in theyarn under-examination butthat the magnitude of such recurrent. deviations is. :not constant.(Compare the amplitudes of the curve b at the antinodes).

The circuits for each of motors 320 to 32m are like that described formotor Mia-except that each is designed to pass the selected frequencyheretofore specified. The corresponding curves 0 to m on chart 68indicate that in the particular stretchof yarn just analyzed, there areperiodicities, in addition to the-forty'foot periodicity indicated bycurve I), often feet, and of eight inches. These periodicities areindicated by the curves d and h,'and the absence of other periodit isonly necessary to convert the alternating current output from filters66b, 660, etc., to direct current by insertion of, for example, a 6H6tube between the filters 6612, etc., and the cathode followers 281),etc., as indicated in Fig. 40. for the circuit of pen motor 321). InFig. 4a, the 61-16 converting tube is indicated diagrammatical- 1y at861) and the curve traced by motor 322) at I). Also, if desired,indicator lamps, may be provided for each channel, as indicated at 82bin Fig. 4a.

The above described analyzer of Fig. 4, with or Without the modificationillustrated in Fig. 4a,,

and designed for the determination of the before specifiedelevenperiodicities, in addition to the roughness indicator, will ordinarilybe sufiicient for the indication of all periodicities apt to occur inyarn manufacture.) In fact, fewer frequency channels could be employedwith satisfactory results. On the other hand, even without increasingthe number of frequency channels, the apparatus could be made to respondto dilferent' periodicities by changing the rate of feed of the yarnthrough the meter. yarn speed is doubled, the periodioities'indicated bythe respective pen motors will likewise be doubled.

The information obtained from the operation of the apparatus of Fig. 4is valuable in locating the source of the yarn diameterdeviations.

For example, the curve It showing .periodicity of eightinches, indicatesthat there may be faulty operation of the yarn spinner, probably of oneor the other or of both of the draft rolls and these parts should bechecked. The curve (2, showing periodicity of: ten feet, indicatesprobable irregular drafting operation in the machine immediatelypreceding theyarn spinner. Knowing the peripheries and rotating speedsof the various rolls used in the production of the yarn, the location ofthe source of this periodicity can be fairly accurately estimated.Similarly, the curve 2) showing a periodicity of forty feet indicatesthat the source of the trouble should be sought still further back inthe processing of current, and the power amplifier or cathode follower2811.. From the displacement of curve n from itsbase line, it isapparent that the yarn 2 isfuzzy, as diameter deviations occurring at intervals of one-fourth inch or less are'indicated.

In Fig. 4, the pen motors, except pen motor 327, respond oppositely toopposite half cycles the yarn. In any given mill utilizing the apparatusof Fig. 4 or 4a., a chart can be compiled, either on the basis ofcalculation or. as a result of use of the apparatus, telling where tolook for faulty operation according to each periodicity indicated by theapparatus.

The invention has now .been'described with.

reference to the relatively simple meter and recorder of Fig. 1, themodification of Fig. 2, and the complete meter, analyzer and recorder ofFig. 4. Although the information given by the system of Fig. 4 is morereadily interpreted, much of it could be obtained from a study of thegraphs obtained by the more simple, and hence less expensive apparatusof Figs. 1 and 2. Although the complete analyzer of Fig. 4 has beenindicated as having twelve. specific frequency channels,

obviously the invention is not limited to this particular number ofchannels nor to the specific selected frequencies. Various changes inthe various oircuitsoould be made Without departing from the spiritofthe invention, andparts of the system could be employed withoutemployment of other parts, as will be apparent For example, if .the

of diameter variations of filamentary material other than yarn, as forexample, wire, glass or the like.

The following is claimed:

1. A diameter meter and recorder for travelling yarn comprising aresistor, photoelectric means for creating a potential difference acrosssaid resistor varying with departures of the yarn diameter from apredetermined value, means for amplifying said potential difierence, apair of power amplifiers each connected to said amplifying means, adevice energized by one of said power amplifiers for continuouslyrecording said amplified potential difference in terms of yarn diametervariations, and a second device and damping means therefor energized bysaid second power amplifier for continuously recording said amplifiedpotential difierence in terms of average variations of yarn diameter,said devices including styli positioned to produce in juxtaposedrelation traces representing diameter variations in the same section ofyarn.

2. A yarn diameter meter and recorder according to claim 1 including aplurality of frequency responsive circuits connected in multiple to saidamplifying means, each of said circuits being responsive to a differentfrequency and one of said circuits being responsive to all frequenciesabove a predetermined value, and a plurality of recording devices, oneconnected to each frequency responsive circuit, said plurality ofrecording devices including recording styli positioned to produce anarray of juxtaposed traces, each trace representing a differentperiodicity in yarn diameter variations in the same section of yarn.

3. A yarn diameter meter and recorder comprising a resistor,photoelectric means for creating a potential difierence across saidresistor varying with departure of yarn diameter from a predeterminedvalue, an amplifier connected across said resistor, a cathode followerconnected to said amplifier, diameter recording means connected to saidcathode follower so as to be energized in accordance with departures ofthe yarn diameter from a predetermined value, a second cathode followerconnected to said amplifier, a diameter recording means connected tosaid second cathode follower so as to be energized thereby and dampingmeans between said second cathode follower and the recording deviceenergized thereby, whereby average yarn diameter variations are recordedby said last mentioned device, said recording means including recordingstyli positioned to produce in juxtaposed relation traces representingdiameter variations in the same section of yarn.

4. A yarn diameter meter and recorder comprising in combination, asource of light, a pair of photoelectric cells positioned to receivelight from said source, means for passing yarn, diameter variations ofwhich are to be recorded,

' between said source and one of said cells, a pair of series connectedsources of energy, one having its positive terminal connected to theanode of one of said cells and the other having its negative terminalconnected to the cathode of the other of said'cells, a resistor havingone end connected to the other terminal of each of said sources and itsother end connected to the other electrode of each of said cells, meansfor amplifying potential differences appearing across said resistor andrecording devices controlled by said amplifying means, said recordingdevices including a pair of pen motors one connected for rapid responseto variations in magnitude and direction of the amplifier output and theother damped for slower response to the amplifier output, and a chartdriven in timed relation with the movement of yarn past the light sourceforreceipt of graphs traced by. the pens of said motors.

5. A yarn diameter meter and recorder comprising in combination a lamp,an alternating current source for said lamp, a battery interposedbetween said source and said lamp, a photocell positioned to receivelight from said lamp, means for moving yarn, variations in the diameterof which are to be recorded, between said lamp and said cell, a circuitfor said cell including a source of energy, an alternating currentamplifier cou-- pled to said circuit, and recording devices controlledfrom said amplifier, said recording devices including a pair of penmotors one connected for rapid response'to variations in magnitude ofthe amplifier output and the other damped for slower response to theamplifier output, and a chart driven in timed relation with the movementof yarn past the light source for receipt of graphs traced by the pensof said motors. Y

6. A filament diameter analyzer comprisingin combination photoelectricmeans for creating a potential difference responsive to changes infilament diameter from a predetermined value,

. means for feeding a filament continuously past said responsive means,means for amplifying the potential difierence created by said responsivemeans, a plurality of circuits responsive to different frequenciesconnected'in multiple to said amplifying means and indicating meansconnected to said circuit whereby the output of the amplifier may beanalyzed to determine periodic recurrences of filament diametervariations.

'7. The filament diameter analyzer according to claim 6 wherein saidindicating means comprise a plurality of recorders each controlled byone of said frequency responsive circuits and having a common chartdriven in timed relation with said filament feeding means and positionedfor simultaneous recording thereon.

8. The analyzer according to claim 6 wherein each of said frequencyresponsive circuits includes means for converting alternating currentfiowing in the circuit to direct current, a power amplifier in eachcircuit for amplifying the" converted current and wherein saidindicating means comprise a recording device associated with eachcircuit and energized by the output from the respective power amplifier.

9. A filament diameter analyzer comprising in combination electronicdiameter responsive means energized in accordance with changes infilament diameter from a predetermined value, means for feeding acontinuous length of filament past said responsive means, a plurality ofcircuits responsive to different frequencies connected in multiple tosaid responsive means, and indicating means connected to each of saidcircuits whereby the output of said responsive means may be analyzed todetermine periodic recurrences of filament diameter variations.

10. The analyzer according to claim 9 wherein said indicating meanscomprises a plurality of recorders, each controlled by one of saidfrequency responsive circuits for recording the dif-' ferentperiodicities detected thereby.

ll. A filament diameter analyzer comprising in combination electronicdiameter responsive means energized in accordance with changes infilament diameter from a predetermined value, means for feeding acontinuous length of filament past said ferent periodicities detectedthereby, a recording device controlled from said diameter responsivedevice so as to record diameter variations irrespective of periodicity,a damped recording device controlled from said diameter responsivedevice so as to record average diameter variations, said recordingdevices including a common chart moved in timed relation with the feedof the filament and positioned'for simultaneous recording thereon of thedifierent periodicities-of diameter variations, of diameter variationsirrespective of periodicities and of average diameter variations.

12. Apparatus for detecting specific periodicities in yarn diametervariations comprising in combination a photoelectric yarn diameter meterfor creating a control current varying with the diameter of yarntraveling past the meter, an amplifier for the created control current,a plurality of circuits connected in multipleto the output of saidamplifier, frequency selective means in each circuit, each frequencyselective means being adapted to pass a frequency corresponding to adifferent specific periodicity to be detected, and means for recordingthe currents passed by each of said frequency selective means.

13. A device for measuring and recording yarn 10 diameter duringmovement of said yarn, diameter responsive means associated with saidmoving yarn for detecting diameter variations from a predeterminedvalue, means coacting with said diameter responsive means operative totranslate said yarn diameter variations into an electric signal ofvarying strength, means for amplifying said electric signal, a pair ofpower amplifiers each connected to said amplifying means, a deviceenergized by one of said power amplifiers for continually recording saidamplified electric signal in terms of yarn diameter variations and asecond device including damping means energized by said second poweramplifier for continually recording said amplified electric signal interms of average variations of yarn diameter, said devices beingarranged to produce in juxtaposed relation traces representing diametervariations in the same section of yarn.

FRED P. STROTHER.

References Cited in the file of this patent.

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